Regarding Mod 73 and SB15
Sorry I have been out of touch...More on that some other day.
Mod 73 is elongated on the top and bottom. However in reality the
bottom hole is not as critical and many of you still have a round 1/4 to
retain the pip pin ball retainers and have had no problem, but it should
be elongated just a bit top and bottom.
The reason the lower hole not being elongated doesn't cause an issue is
that the loose tailplane is going to move but the pin itself with only
one hole elongated will still allow sufficient small movement of the
tailplane and its TP6 bushing glued in to move so as not to crack the
bearing free. Unless your tailplanes flop about independently a lot.
Only the underside of the TP5 with its mandated extra glass retains the
pin in this modification. However, the pip pin is normally not long
enough for the added glass work, (Note the epoxy and glass should not be
relieved in the vicinity of the hole to allow the retaining balls to
catch and retain the existing pin, you must buy a longer pin (2 inch
works)). Note SB 15 must be followed to remove all play in the
tailplane pitch tube system along with this mod.
That said, let me say this. No movement of the tail plane should be
noticed at the trailing edge. Nor should the stab move independently of
the mass balance arm. The inspection documentation only states:
* Tab drive pin and bracket for corrosion, cracking.
* Main tailplane bushes for security and cleanliness.
* Tailplane drive bushes in inboard rib for wear and security.
A small amount of bushing wear and pin fit will allow the tailplane to
move no more than 1/64 inch at the rear and in a properly built
tailplane, the stabs when gripped at the trailing edge will not move
independently from one another at all. If they do, something is worn or
built incorrectly. Any tailplane movement will, due to the fact the
physical tail plane is not balanced, flutter unless it is secured
soundly through the TP13 bushes to the drive pins and the drive
mechanism is soundly attached to the TP4 tube and mass balance arm via
the TP14s. Hence Mod 73 is a Band-Aid, to the real problem of sloppy
TP14 pins and TP13 bushes.
The real fix is to do the work right. TP14 pin installation to a tight
fit is essential. The PFA mod 10672 bonding in the bushes was a
terrific idea to prevent many problems, from TP5 de-bonding, to foam
protection from lubrication and a more sound TP5 adhesion to the foam
stab core and ply rib. Many of you have installed a threaded cap for an
additional safety lock for the tailplane pip pin. Extra glass was added
in doing this and frankly cured part of the problem of the TP5
retention. Accidents tend to cause Band-Aid solutions. I know I have
beat a dead horse on TP14 pin installation techniques in the past.
However, the SB15 Loctite solution is a quick and easy fix to slightly
loose pins and makes the TP12 and TP9 retention problems go away. Also
some of you developed clever clamping fixtures to secure the drives to
the tubes which was another mechanical solution that worked. (By the
way, don't get the Loctite 603 into the pitch bearings, that stuff
really works.) The Band-Aid solution to prevent one part of the problem
for he who does not understand that any movement of the stab due to
excessive play or wear in any part of the stabilator control system is
reason to ground the aircraft until corrective action is made.
So to cause trouble:
The TP14 C and D pins should not allow the TP12 or TP9 to move on the
TP4 Tube at all. That said, most builders note that a small ticking
sound but no perceptible movement of the TP12 or 9 is noticed on annual
inspections as the plane ages with no modification. Once the movement
begins though, it gets worse. Any perceptible movement indicates SB 15
is needed and cures the problem...
I know that in the past the factory suggested up to 1/2 inch movement of
a tail plane was acceptable, but that means you have a known flutter
problem and are flying with a known malfunction in a flight control
system. In the 80 HP aircraft flying at or near 100 Kts it is not a
problem, but in a dive to VNE, flutter is a very real concern. I have
had to rebuild 4 stabilators due to this type wear. The pilots never
realized that they had movement nor did they know how to check. Flutter
clearly occurred as the wear on the TP13s was evident as well as flat
spots in the TP14 pins, however the TP5 was undamaged. The preflight
check for proper fit and security is quite simple and must be done on
each preflight. Grasp the stabilator at the trailing edge and pull up
lightly to put the mass balance weight on the stop. With the mass
balance arm against the stop pull up and check if the tailplane moves
beyond the clunk of the mass balance stop (Checks TP9 and 12 Pins). No
movement should occur on either the up or down stop. At the leading
edge of the stab grab the leading edge of both stabilators and attempt
to move them up and down independently or if you have longer arms from
the trailing edge, move the stabs by gripping the trailing edge outboard
of the tabs and moving them one up and one down and vice versa to check
for independent movement of the stabs between one another. (Checks
TP12s)
Keep it tight and right
Best Regards,
Bud Yerly
Tech Support
----- Original Message -----
From: Keith Hickling<mailto:keithhickling@clear.net.nz>
To: europa-list@matronics.com<mailto:europa-list@matronics.com>
Sent: Sunday, September 30, 2012 10:27 PM
Subject: Re: Europa-List: Mod 73
<keithhickling@clear.net.nz<mailto:keithhickling@clear.net.nz>>
I'm pretty sure you are correct, both top and bottom holes need to be
elongated, otherwise it would not achieve the purpose which is to
prevent
torque loads from the torque tube being transmitted through the TP6
sleeve
with the possible result of disbonding. That is what I did.
Regards,
Keith Hickling,
New Zealand.
--------------------------------------------------
From: "egp8111" <egp8111@aol.com<mailto:egp8111@aol.com>>
Sent: Monday, October 01, 2012 11:37 AM
To: <europa-list@matronics.com<mailto:europa-list@matronics.com>>
Subject: Europa-List: Mod 73
<egp8111@aol.com<mailto:egp8111@aol.com>>
>
> I'm returning my early monowheel classic to flying status after a
number
> of years being inactive. Getting caught up on the mods. I'm in the
process
> of doing mod 73 the tailplane retention mod. Just a question for my
> clarification. Are both the top and bottom pip pin holes on the
torque
> tube elongated or just the top ? I assume both top and bottom holes
> receive the same treatment but the directions on the factory website
leave
> me with just a bit of doubt. I tried contacting Europa directly and
got a
> nice email from someone saying she didn't know but was passing my
question
> on to the technical staff but thats the last I have heard from them.
Can
> someone clear this up for me please.
>
> Thanks,
>
> Skip Pate, Europa sr. # A009 monwheel classic 178 hr. TT first flown
1996
>
>
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